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Piezoelectric Ceramics

Piezoelectric Ceramics. Dr. & Prof. Chun-Huy Wang Electronic Engineering Nan-Jeon Institute of Technology Tainan, Taiwan. OUTLINE. Introduction Electronic Ceramics Piezoelectricity Piezoelectric Ceramics Fabrication Process of Piezoelectric Ceramics

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Piezoelectric Ceramics

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  1. Piezoelectric Ceramics Dr. & Prof. Chun-Huy Wang Electronic Engineering Nan-Jeon Institute of Technology Tainan, Taiwan

  2. OUTLINE • Introduction • Electronic Ceramics • Piezoelectricity • Piezoelectric Ceramics • Fabrication Process of Piezoelectric Ceramics • Piezoelectric Ceramics: Applications

  3. Dielectric Piezoelectric Pyroelectric Ferroelectric ＜Electronic Ceramics ＞ Dielectric Property Piezoelectricity Pyroelectricity Ferroelectricity

  4. Piezoelectricity Mechanical and electrical energy conversion phenomena, discovered by France Scientist Pierre and Jacques Curie brother in 1880. Direct Piezoelectric Effect Mechanical Electrical Converse Piezoelectric Effect

  5. Piezoelectric Ceramics The famous one is the lead zirconium titanium, Pb(Zr,Ti)O3 [abbrev. as PZT]. PZT was first reported as ferroelectric materials in 1950 by Shirane et al., and reported as a useful piezoelectric materials by Jaffe et al. in 1954. Below the Curie temperature, PZT ceramics is ferroelectrics with piezoelectricity, and it was paraelectrics without piezoelectricity at the temperature higher than Curie Temperature.

  6. Piezoelectric Ceramics • The crystal structure of most traditional piezoelectric ceramics are pervoskite structure, with the chemical formula as ABO3. • A is a larger divalent metal ions, usually lead(Pb) or barium(Ba). Located at the corner of the cubic. • B is a smaller trivalent metal ions, usually titanium(Ti) or zirconium(Zr). Located at the center of the cubic. • O is oxygen ion. Located at the center of the faces.

  7. Piezoelectric Ceramics cornal • (perovskite)結構，化學式為 center face center Pervoskite structure, with the chemical formula as ABO3 e.g. : BaTiO3

  8. Piezoelectric Ceramics

  9. Piezoelectric Ceramics For a three-dimensional unit cell, there are six possible directions to displace the central positive ion towards the face centered negative ions.  Therefore, there are six different choices for spontaneous polarization in the ferroelectric phase,

  10. Piezoelectric Ceramics

  11. Piezoelectric Ceramics

  12. Fabrication Process of Piezoelectric Ceramics K2CO3、Nb2O5、TiO2、Bi2O3、Na2CO3 (1-x)(Na0.5K0.5)NbO3-x Bi0.5(Na0.93K0.07)0.5TiO3 x varied from0.02、0.04、 0.06、0.08、 0.10 Weighting according to formula Ball mill to mix Ceramics prepared by conventional mixed oxide method Drying & Grinding powder Calcining 950℃/4h Next page

  13. Previous page Polymer binder Ball-Mill to grind Form to near finished Ddiameter=15mm Measuring Density SEM、XRD Remove binder Sintering1100℃ 3~7 h Surface grind t=1mm Silver paste on electrodes MeasuringC1KHz、D1KHz Poling100℃~250℃ 4 kV/30min fr、R、fa 、C1KHz、D1KHz kp、kt、K33T

  14. Fabrication Process of Piezoelectric Ceramics Sinteringand poling are two important key fabrication processes related to the microstructure of the PZT ceramics. The sintering process gives the grain structure for the ceramics and the poling process gives the piezoelectric effects for the ceramics. The final grain size and the perfect crystal formation depend on the temperature and time of the sintering process.

  15. Domain and domain boundaries of polycrystalline BaTiO3 (left)domain structure of unpoled ferroelectric ceramics (right) graphical representation

  16. Poling Poling is the final process in the fabrication. Initially, unpoled ceramics have no piezoelectricity because the piezoelectric tensors of the grains are randomly oriented. During the poling process, ferroelectric switching occurs and creates non zero overall piezoelectric tensors.

  17. Poling (left)unpoled, (center)during poling, (right)after poling

  18. P~E Curve

  19. P-E curve vs Voltage Applied

  20. 壓電陶瓷材料應用之分類 壓電陶瓷按照應用分類共分爲七大類： 一、 壓電振盪及材料 二、 壓電聲電元件：蜂鳴器、送話器、受話器、壓電喇叭 三、 壓電超音波換能器：超音波清洗、超音波霧化、超音波美容、超音波探測 四、 資訊處理元件：濾波器、諧振器、檢波器、監頻器、表面聲波、延遲線 五、 動力裝置：點火器、超音波切割、超音波粘接、壓電馬達、壓電變壓器 六、 壓電感測器：速度、加速度計、角速度計、微位移器 七、 光電元件：光調節器、光調節閥、光電顯示、光資訊儲存、影象儲存和顯示

  21. Ceramics Resonator Resonator is the basic frequency control component, the piezoelectric filter is composed by the piezoelectric resonator .

  22. Ceramics Resonator

  23. Ceramic Filter Monolithic Filter (used for low frequency)

  24. SAW Resonator and Filter 表面聲波(surface acoustic wave，簡稱SAW)是在1885年由英國物理學家Lord Rayleigh所發現，故亦稱為Rayleigh波，初期主要應用在地震學方面的研究。Rayleigh波是由一個壓縮波及一個剪向波相耦合而成，若表面聲波在壓電基板上傳播，則會在基板上產生相對應的時變電場。

  25. SAW Resonator and Filter In natural world, SAW can create by earthquake. In engineering, SAW can create by piezoelectric effect.

  26. SAW Resonator and Filter

  27. SAW Resonator and Filter One Port Resonator

  28. SAW Resonator and Filter Two Port Resonator

  29. SAW Resonator and Filter Applications of SAW Resonator

  30. 振盪子產品應用實例 霧化振盪子用於加濕機、精油霧化以及醫療霧化領域

  31. 超音波加濕器 超音波加濕技術具有加濕效率高、電耗低、穩定性好、安全性高的特點，可以實現溫度控制與濕度控制的相互獨立、互不干擾。

  32. 振盪子產品應用實例 美容復健用超音波按摩頭

  33. 空中換能器應用實例 • 汽車倒車雷達

  34. 致動器 螺旋式 致動器應用:微形馬達, 手機, 數位相機

  35. 致動器應用於相機鏡頭模組

  36. 壓電陶瓷變壓器的應用

  37. 單層壓電變壓器應用實例 單層式壓電變壓器：用於臭氧產生器、 負離子產生器、 靜電消除裝置、電子口罩等等高壓產生單元模組

  38. 積層壓電變壓器應用實例 積層式壓電變壓器：用於筆記型電腦液晶顯示器、桌上型電腦液晶顯示器、個人數位助理(PDA)、數位相機(DSC)、數位攝影機(DSC)之冷陰極管電源模組等。

  39. 蜂鳴器 回饋式蜂鳴片 外激式壓電蜂鳴器 自激式壓電蜂鳴器 壓電蜂鳴片 • 蜂鳴器的作用 蜂鳴器是一種一體化結構 的電子訊響器，採用直流電壓供電，廣氾應 用於計算機、印表機、影印機、報警器、電 子玩具、汽車電子設備、電話、定時器等電 子產品中作發聲元件。

  40. 壓電式平面喇叭 • 經由雙簧式壓電致動器出力使基板產生振動從而構成一揚聲機制：用於行動電話、個人數位助理(PDA) 、筆記型電腦等之發聲模組 Distributed Mode Actuator (DMA)

  41. Harvesting Energy Application Energy harvesting (also known as Power harvesting or energy scavenging) is the process by which energy is derived from external sources (eg solar power, thermal energy, wind energy, salinity gradients and kinetic energy), captured and stored.

  42. Power Platform • 2007年兩位MIT的學生提出在都市區域內建立壓電地板的觀念[source: Christian Science Monitor]，他們的構想是在鬧區例如火車站、購物商場建立壓電地板來利用人們行走的步伐所產生的機械能轉換成為電能。雖然人們每一步所產生的電力非常小約只能點亮兩個60W燈泡一秒鐘，但如果有很多人在行走則可以產生相當大的能量。

  43. Power Platform • 2008年以色列的Innowattech公司開始利用所生產的IPEG (Innowattech Piezoelectric Power Generator)發電器來試驗建構壓電道路

  44. Power Platform • 2010年 Innowattech公司再與以色列國家道路公司(Israel National Road Company，INRC)合作建構壓電鐵路。

  45. Power Platform • 日本東日本鐵路公司(East Japan Railway Company，JR East)在2008年初在東京車站的收票口建立壓電地板，利用此一地板來產生發電，到目前每天發的電力為1,400kW/sec。

  46. Harvesting Energy Application Most piezoelectric electricity sources produce power on the order of milliwatts, too small for system application, but enough for hand-held devices. Piezoelectric generators are suitable for power industrial wireless sensor applications.

  47. Thank you！

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